Underwater release device

ABSTRACT

A device for releasing load tension from submerged objects, such as a mooring line in tension, which device may be remotely operated to effect release and is comprised of an outer container, load attachment means, a stored energy source, a thermally fusible link element, switching components, sensors, such as attitude or pressure depth, and a force-multiplying mechanical release mechanism wherein the stored electrical energy is released upon command to fuse said link element and thereby permit said mechanical release mechanism to uncouple one of said load-attachment devices.

United States Patent 1 1 Davidson [451 July 31,1973

1 1 UNDERWATER RELEASE DEVICE [76] Inventor: William M. Davidson, Box74,

Mountain Lakes, NJ. 07046 [22] Filed: Dec. 2, 1971 [21] Appl. No.:204,070

Primary ExaminerHerman J. Hohauser Assistant Examiner-William J. SmithAttorney-William M. Davidson [57] ABSTRACT A device for releasing loadtension from submerged objects, such as a mooring line in tension, whichdevice may be remotely operated to effect release and is comprised of anouter container, load attachment means, a stored energy source, athermally fusible link element, switching components, sensors, such asattitude or pressure depth, and a force-multiplying mechanical releasemechanism wherein the stored electrical energy is released upon commandto fuse said link element and thereby permit said mechanical releasemechanism to uncouple one of said load-attachment devices.

5 Claims, 5 Drawing Figures (L 2122 25 I 3 3;; M i/ 23 UNDERWATERRELEASE DEVICE This invention relates to an underwater release devicewhich may be used as a part of a mooring system or, optionally, may beincorporated as an integral component of another device that requires arelease mechanism in order to perform its function. Operation of therelease device can be controlled by a variety of means, including,manual switch, attitude change, pressure depth, electric cable, timedelay or acoustic receiver.

Other release devices, currently in use, include explosive mechanisms,shear pins and motor-driven power trains. Explosive devices requirespecial care and handling for storage, transport and operation and, inmany instances, interfere with swimmers or underwater acoustic devices.The operation of both the explosive and motor-driven types of releasedevices require transmission of electric current by wire to the releasedevices, both of which require substantial current or power.

This invention provides a non explosive release device that can berefurbished in the field by replacement of the fusible link element.Further, the release can be operated in a variety of ways with low inputsignal power; in one instance, a briefpulse current of IO milliamperesis sufficient to operate the release device. These advantages areachieved through the use of lowimpedance switches in combination withlowimpedance storage devices for electrical energy, such as nickelcadmium batteries or capacitor discharge elements. All of the electricalcomponents are isolated from sea water and the underwater environment bymeans of a pressure-sealed external container or housing.

One object of this invention is to provide an underwater release devicethat is simply constructed, compact, reliable and safe to store andhandle as well as low in cost.

Another object of this invention is to provide a release device thatdoes not involve the use of explosives and can be operated in the samearea with personnel or with other underwater acoustic devices.

Another object of this invention is to provide a release device thatcontains its own stored electrical energy as required for its operationso that it can be used and operated independently from external sourcesof power even after six months to a year in the water environment.

Another object of this invention is to provide a release device that canbe readily altered to permit control by a variety of means, eitherremotely or manually, including, manual switch, attitude change,pressure depth, electric cable, time delay or acoustic receiver.

Still another object of this invention is to provide a release devicethat can be refurbished and reused in the field without complex toolingor equipment being required.

Other objects, advantages and novel features of this invention willbecome apparent from the following description of the invention whenconsidered in conjunction with the accompanying drawings wherein:

FIG. 1 illustrates pictorially one use of this invention as a cablerelease when operated in combination with an acoustic receiver forrecovery ofa moored array of instruments.

FIG. 2 presents an electrical schematic wiring diagram for the essentialelements of this invention and their electro-mechanical functionalrelationships.

FIG. 3a shows a plan view ofa typical release device completelyassembled. FIG. 3b shows a cross-section view at location b-billustrating the internal mechanisms. FIG. 3c is a cross-section view atlocation a-a to further illustrate the power-pack section.

Referring in greater detail to the drawings, one application of therelease device is illustrated in FIG. 1. Release device I is coupled atits upper end to plastic rope 2 and at its lower end to acousticreceiver 3. Current meter array 4, also secured to rope 2, is suspendedat depth by means of subsurface buoy 5 which furnishes buoyancy tomaintain rope 2 in tension against mooring 6 and the negative buoyancyof current meters 4. When it is desired to recover instrument array 4,surface ship 7 transmits an acoustic signal through the water toacoustic receiver 3 which, in turn, transmits an electrical pulse bydirect wire means (not shown) to release device 1. Release device 1converts the electrical pulse signal into mechanical action thatuncouples release device 1 from acoustic receiver 3, thus allowing buoy5 to lift meter array 4 to the ocean surface for recovery operations bysurface ship 7.

FIG. 2 shows schematically the electro-mechanical elements of releasedevice 1. Fusible link 8, which may be made of fine wire, such asstainless steel wire 3 to 10 mils in diameter, is electrically connectedbetween the anode of low-impedance operating switch 9, which may beeither a silicon controlled rectifier or a mercury switch, and oneterminal of low-impedance energy source 10, which may be nickel-cadmiumstorage batteries or capacitor elements. The electrical circuit betweenenergy source 10 and the cathode of operating switch 9 may be completedby arming switch 11, which may be a mechanically-operated single-pole,singlethrow switch having low impedance. Closing operating switch 9causes discharge of current from energy source 10 through arming switch11 and fusible link 8; current flow through link 8 causes it to fuserapidly and free mechanical release element 12. Operating switch 9 maybe closed by signal from remote control source 13, such as an acousticreceiver or external cable, which furnishes a small gating current inthe order of 10 milliamperes. If operating switch 9 is a mercury switch,it can be closed by tilting the switch through a prescribed angle oftilt in any direction from vertical. Terminals 40 can be used either tomeasure the condition of energy source 10 or for recharging purposessimply by replacing switch 11 with a test plug designed for suchpurposes.

FIG. 3 illustrates atypical embodiment of release device l inelectro-mechanical structural form. FIG. 3a shows an external plan viewof release device 1 with attachment devices 14 and 15 for cableattachment, wherein terminal 14 can be released upon command. Armingswitch 11 and electrical feed-through 16 are mounted on end plate 17which is secured to housing 19 by bolts 18.

Internal components of release device 1 are illustrated by cross-sectionview bb in FIG. 3b. Housing 19, designed as a pressure vessel towithstand hydrostatic pressure, contains power pack 21 and rotaryactuator 26. End plate 17 and seal 29 together with housing 19 form acomplete pressure vessel together with suitable seals for electricalfeed through 16 and rotary shaft 28. Power pack 21 includes energysource 10, which as illustrated consists of two nickel-cadmium storagebatteries, a solid-state operating switch 9, arming switch 11, controlsource 13 with electrical feed through 16, fusible link 8, supportedbetween ground support arm 22 and bus bar 23. Link 8 is electricallyinsulated from support arm 22 by means of insulator 24. Bus bar 23connects batteries 10 in parallel at their anodes. Electricalconnections (not shown) are provided to complete the electricalcircuitry of power pack 21 so that arming switch 11, operating switch 9,control source 13 and link 8 are connected as illustrated in FIG. 2.Power pack 21 is inserted in housing 19 so that link 8 engages andrestrains lever arm 25 of rotary actuator 26 against the torque oftorsion spring 27. Shaft 28 of actuator 26 is sealed to gland 30 bymeans of seal 31. Gland 39 is sealed to housing 19 by means of seal 32.Pinion gear 33, attached to the end of shaft 28, engages spur gear 34which drives latches 35 through a suitable gear train designed fortorque multiplication. Latches 35 are held in engagement with detents inpin 36 by means of tension springs 37. Cavity 38 within housing is opento sea water through hole 39 which provides clearance for pin 36attached to release terminal 14. A multiplicity of release mechanismscan be applied for the release of pin 36 employing mechanical advantagetoward the end that the force required to restrain lever arm is only afew pounds, while the tensile force applied to cable release terminal 14can be several tons. Further, a preferred alternate design approachwould be to incorporate the gear train, including gears 33 and 34,within the protective enclosure of housing 19.

FIG. shows a cross-section view at location a-a to further illustratethe arrangement of batteries 10, arming switch 11 and operating switch 9within power pack 21. Arming switch 11 may be eliminated if desired, oralternately, external operation of switch 11 can be provided through useof a rotary switch nob accessible from end plate 17 of FIG. 3a. Asolid-state relay may be substituted for operating switch 9 when it isdesireable to activate release device 1 from an external control source13, which may be an acoustic receiver or manual control stationconnected by electric cable to device 1. The command signal to operatedevice 1 is fed from control source 13 and enters device 1 throughelectrical feed-through 16 into solid-state relay 9, as a gating impulsethat causes relay 9 to conduct current between its anode and cathodeterminals. Alternately, a mercury type tilt switch (not illustrated) maybe used in place of relay 9 to serve as an attitude sensor when it isdesired that device I operate automatically by change in its attitude,such as may be caused by the slackening ofa cable in a moored array orby the sudden tumbling of another underwater device of which device 1 isan integral part. External control source 13 is not required either formanual operation of device I, such as the operation of switch 11 by adiver, or for automatic operation by a tilt sensor, such as a mercuryswitch used for operating switch 9.

In operation, the apparatus identified as device 1 will be transportedto the point of use with link 8 installed and energy source 10 fullycharged, except when capacitors are used for energy source 10 it ispossible to accomplish charging in situ prior to operation of device 1.Provision can be included for insertion of a special test plug in placeof switch 1 1 to permit field testing the condition of energy source 10and for recharging either when using batteries or capacitors. Armingswitch 11 is retained in the open position to insure that device 1cannot operate prior to being installed. After device 1 is connected tothe mooring system or other ocean equipment and is ready to be loweredto depth, device 1 can be armed by closing switch 11. Device 1 can alsobe made part of an acoustic receiver or incorporated as an integral partof other types of ocean equipment, such as lift recovery devices,wherein the release of a cable or lever is required to initiateoperation or deployment at depth.

In the mooring line application, illustrated in FIG. 1, acousticreceiver 3 becomes control source 13 and is connected to device 1 bymeans of electric cable (not shown) entering device 1 throughfeed-through 16. Surface ship 7 transmits a command signal by acousticmeans to acoustic receiver 3 which contains its own power for operation.Acoustic receiver 3 then feeds a small electric pulse (about 10milliamperes) to device 1 through the connecting electric cable. Thecontrol pulse enter the gating circuit of relay 9, as depicted by FIG.2. Relay 9 then permits current to flow from energy source 10 throughswitch 11 and fusible link 8 because a conductive path, offeringlow-impedance, is immediately established between its anode and cathodeelements. Fusible link 8 is designed to weaken and fuse rapidly whensubjected to a pulse current of about 10 amperes peak. Link 8 thenreleases lever arm 25 which initiates operation of rotary actuator 26 torelease pin 36.

An alternate method of control for operating device 1 can be obtained byomitting acoustic receiver 3 and extending a two-wire electrical cablefrom device 1 to surface ship 7 control station. Actuation of device 1can then be accomplished by wire transmission of a small electric pulsefrom surface ship 7 control to device l and into the gating circuit ofswitch/relay 9. Other methods for remote control operation of device 1are readily obtained by substitution of conventional switching devicesin place of acoustic receiver 3, as for example, a timer switch orpressure switch in combination with a source d-c potential to send acontrol pulse to the gating circuit of relay 9.

Still another method of control for operating device 1 can be obtainedfrom the same basic device 1 simply by using a mercury tilt type switchin place of relay 9. Such a mercury switch has only an anode-cathodecircuit and does not require a gating input or an external controlcable. The mercury switch can be selected to be normally open when heldin one orientation, such as vertical. When tilted from vertical in anydirection by a specified spherical angle of tilt, preferably at leastthe mercury will bridge the switch terminals and close the circuit.Small mercury switches, as currently available, have both low impedanceand ample current capacity for repeated use of the kind required fordevice I. Also, provision can be made to preventagitation of themercury, during normal use, from causing accidental switch closure.

As will be apparent to those skilled in the art in the light of theforegoing disclosure, many modifications, alterations and substitutionsare possible in the practice of this invention without departing fromthe spirit or scope thereof.

I claim:

1. A release mechanism, the combination comprismg:

releasable coupling means including a relatively fixed member and areleasable member releasably coupled together with force multiplyingmeans;

actuator means rotatable between an armed position for engaging andholding said releasable member in its coupling position, and a disarmedposition for uncoupling said releasable member;

biasing means urging said actuator means from its armed to its disarmedposition; locking means for engaging and retaining said actuator meansin its armed position consisting of a fusible link which, in response tocommand, is thermally fused by electric current means, thereby releasingsaid actuator means for rotation by said biasing means to its disarmedposition; electrical energy means to supply said electric current meansfor melting said fusible link;

communicating means for connecting said electrical energy means withsaid fusible link, including manual arming switch and operating switchmeans responsive to command.

2. In a release mechanism, the combination in accordance with claim 1,and said operating switch means further including a relay, such as asilicon controlled rectifier, responsive to command for connecting saidelectrical energy means with said fusible link.

3. In a release mechanism, the combination in accordance with claim 1,and said operating switch means further including a sensor, such as apressure sensor to sense depth or a mercury switch to sense a change inattitude, an acoustic receiver, a timing device or direct wire tocontrol the closing of said operating switch means.

4. In a release mechanism, the combination in accordance with claim 2,and said operating switch means further including a sensor, such as apressure sensor to sense depth or a mercury switch to sense a change inattitude, an acoustic receiver, a timing device or direct wire tooperate said relay.

5. A release mechanism, the combination in accordance with claim ll,wherein the improvement comprises the substitution of a test plug forsaid arming switch to provide means for monitoring the condition of saidelectrical energy means or a source of new energy.

1. A release mechanism, the combination comprising: releasable couplingmeans including a relatively fixed member and a releasable memberreleasably coupled together with force multiplying means; actuator meansrotatable between an armed position for engaging and holding saidreleasable member in its coupling position, and a disarmed position foruncoupling said releasable member; biasing means urging said actuatormeans from its armed to its disarmed position; locking means forengaging and retaining said actuator means in its armed positionconsisting of a fusible link which, in response to command, is thermallyfused by electric current means, thereby releasing said actuator meansfor rotation by said biasing means to its disarmed position; electricalenergy means to supply said electric current means for melting saidfusible link; communicating means for connecting said electrical energymeans with said fusible link, including manual arming switch andoperating switch means responsive to command.
 2. In a release mechanism,the combination in accordance with claim 1, and said operating switchmeans further including a relay, such as a silicon controlled rectifier,reSponsive to command for connecting said electrical energy means withsaid fusible link.
 3. In a release mechanism, the combination inaccordance with claim 1, and said operating switch means furtherincluding a sensor, such as a pressure sensor to sense depth or amercury switch to sense a change in attitude, an acoustic receiver, atiming device or direct wire to control the closing of said operatingswitch means.
 4. In a release mechanism, the combination in accordancewith claim 2, and said operating switch means further including asensor, such as a pressure sensor to sense depth or a mercury switch tosense a change in attitude, an acoustic receiver, a timing device ordirect wire to operate said relay.
 5. A release mechanism, thecombination in accordance with claim 1, wherein the improvementcomprises the substitution of a test plug for said arming switch toprovide means for monitoring the condition of said electrical energymeans or a source of new energy.